Automatically actuated gate cut-off valve, responsive to pressure drop, with gate sealing means, useful in pressurized waveguides



y 4, 1963 F. J D. TAYLOR 3,089,511

AUTOMATICALLY ACTUATED GATE CUT-OFF VALVE, RESPONSIVE TO PRESSURE DROP, WITH GATE SEALING MEANS, USEFUL IN PRESSURIZED WAVEGUIDES Filed June 23, 1961 5 Sheets$heet 1 FREDER'KK ILDFFAYLO'RV INVENTQR ATTORNEY May 14, 1963 F. J. D. TAYLOR 3,089,511 AUTOMATICALLY ACTUATED GATE CUT-OFF' VALVE, RESPONSIVE TO PRESSURE DROP, WITH GATE SEALING MEANS, USEFUL IN PRESSURIZED WAVEGUIDES Filed June 25, 1961 3 Sheets-Sheet 2 FREDERICK ID,-I7\YLDR' INVENTORI BY W ATTQQNEY May 14, 1963 F. J. D. TAYLOR 3,0

AUTOMATICALLY ACTUATED GATE CUT-OFF VALVE, RESPONSIVE TO PRESSURE DROP, WITH GATE SEALING MEANS, USEFUL IN PRESSURIZED WAVEGUIDES 5 Sheets-Sheet 5 Filed June 25, 1961 FREDERICK JDTAYLO-R \NVENTOR ATTORNEY United States Patent Ofitice 3,89,511 Patented May 14, 1963 AUTOMATICALLY ACTUATED GATE CUT-OFF VALVE, RESPONSIVE T PRESSURE DROP, WITH GATE SEALING MEANS, USEFUL IN PRESSURIZED WAVEGUIDES Frederick John Dunn Taylor, Wembley Park, England, assignor to Her Majestys Postmaster General, London, England Filed June 23, 1961, Ser. No. 119,135 Claims priority, application Great Britain July 21, 1960 11 Claims. (Cl. 137-456) This invention relates to a pressure responsive valve suitable for use in electromagnetic wave guides which, in use, contain a gas at a pressure above that of the atmosphere.

Among the modes of wave propagation which can be supported by a wave guide of circular cross-section, the H mode is characterised :by attenuation which falls as the frequency of the transmitted signal is increased and this mode is therefore advantageous for the long distance transmission of signals at millimetre wavelengths. In use such guides would be filled with a relatively inert gas such as nitrogen at a pressure in excess of that of the atmosphere, and might be buried in the ground. In practice it is essential that means be provided at intervals along the length of the guide whereby in the event of mechanical damage to the guide, water or other unwanted material which may find its way into the guide can be prevented from travelling along the guide for more than a limited distance.

It is an object of this invention to provide means for isolating one section of a wave guide from an adjacent section should a fault condition occur due to, for example, mechanical damage to the guide.

According to the present invention an electromagnetic wave guide has a gap in its wall which extends transversely to the longitudinal axis of the guide, a housing surrounding the gap on the exterior of and in gas-tight relationship with the guide, a closure device in an inoperative position located within the housing and capable of insertion into the wave guide through the gap for closure of the bore of the wave guide, and a closure device operating mechanism including a device responsive to pressure within the wave guide, the arrangement being such that the operating mechanism inserts the closure device into the wave guide when the pressure within the wave guide falls below a predetermined magnitude.

An alternative form of electromagnetic wave guide embodying the invention comprises two axially spaced wave guide sections, a gas-tight housing exterior of the sections bridging the gap between the sections, a closure device located in an inoperative position within the housing and capable of insertion into the gap between the sections for closure of the bore of the wave guide, and a closure device operating mechanism including a device responsive to pressure within the wave guide, the arrangement being such that the operating mechanism inserts the device into the gap between the sections when the pressure within the wave guide falls below a predetermined magnitude.

T he closure device may comprise a vane which is rotatable about an axis lying outside the wave guide and extending parallel to the longitudinal axis of the wave guide, the shape and size of the vane being such that when inserted into the wave guide it obstructs the whole of the bore of the guide. The vane may be provided with sealing means such that, when the vane has been inserted into the bore of the guide, a water-tight seal is formed between at least one side of the vane and the inner wall of the guide.

The invention is particularly suited for use with wave guides having a circular cross-section in which transmission in the H mode is not substantially impeded by circumferential gaps in the wall of the guide.

One forum of electromagnetic wave guide embodying the invention will now be described in greater detail by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is a transverse section of the embodiment taken on the line A-A in FIG. 2, and with certain other parts shown in section for clarity,

FIG. 2 is a longitudinal view; partly in section, taken on the line B-B in FIG. 1, and

FIG. 3 is a longitudinal part section taken on the line 'CC of FIG. 1.

Referring to the drawings, adjacent sections 1 and 2 of a circular cross-section wave guide are separated axially by a gap 3. The two parts of a housing H are clamped together by screws 21, a ring seal 22 being interposed. The housing H bridges and forms a gas-tight enclosure around the gap 3 in order to prevent escape of pressurised gas contained within the wave guide.

The housing H has lower and upper portions N and 19a respectively. Within the upper portion 19: a closure device, shown as a vane H, is rotatably mounted on a shaft 5. The vane 4 is shown in an unoperated position in which a stop 7 interacts with a release pawl 3 to prevent rotation of the vane 4- by a coil spring 6 to an operative position. The stop 7 comprises a nut and bolt secured to the vane. The pawl 8 is pivoted near its upper end on an axle 23 and a shaft 24, secured to an inner wall 25 of the housing H, passes through a slot in the lower end of pawl 8. Spaced pairs of nuts 26 are secured on the shaft 24 and co-act with pawl S to limit its movement. The vane '4 has on one side an annular flexible tube 16 connected by a pipe to a drilled pressure block 12.

An axially flexible corrugated bellows 9 also is mounted within the upper portion 19a and is secured to a wall of the housing by a hollow bushing 27 which communicates with the interior of the bellows. A screw 17 is secured within the outer portion of the bushing 27 to seal the latter. A stub shaft 28 is secured to the lefthand end, as seen in FIG. 2, of the bellows 9 and this shaft passes through an aperture in .the inner wall 2'5. A pipe it connects the interior of bellows 9 with the interior of a valve housing 11 located in the lower por tion 19 of housing H.

Within valve housing 11 is slidable the head 29 of a valve 11a, the hollow stem 13 of which passes through an aperture in housing 11. A sealing disc 15 is interposed between the head 29 and the aperture, the valve head normally being biased by a spring 30 to a position in which it seals the aperture. The walls of the valve stem 13 have apertures 14 and on the outside of the housing a rubber disc 31 surrounds the stern.

in use, the wave guide is filled with a pressurized gas, for example nitrogen, the gas pressure within the bellows being the same as that within the wave guide and within the housing H. The vane 4- is in the position shown in the drawings and valve head 29 closes the aperture in the housing 11. If now, for example, the wave guide becomes fractured the gas pressure within the guide and within housing H drops and the bellows 9 expands axially and shaft 2-8 pivots pawl 8 about its axle 23 thereby releasing the pawl from engagement with the stop 7. The spring 6 then causes the vane to rotate to an operative position in which it is inserted into the gap 3 thereby obstructing the bore of the wave guide. During rotation of the vane 4 to this operative position the pressure block 12 contacts the valve stem 13 and causes valve head 29 to slide within the housing 11 against the action of the spring 30. When the vane 4 is in its fully operative position the apertures 14 communicate .with the interior of valve housing 11 and gas from within the bellows 9 passes through pipe 10 and apertures 14 through the drilled block 12 into the annular flexible tube 16 which becomes inflated. When inflated, tube 16 forms a seal between the internal walls of the wave guide and the vane 4. Any liquid, for example water, which may enter the wave guide through the fracture is prevented by vane 4 from passing further along the wave guide.

After repair of the fracture the screw 17 temporarily is removed from bushing 27 thereby lowering the pressure within the bellows 9 and the tube 16 to that of the atmosphere. The shaft 28 thus moves to the right, as seen in FIG. 2, and the pawl 8 resumes the position shown in that figure. A sealing cap 18 is then removed from the end of the shaft and a re-setting lever (not shown) is used to rotate the shaft until the pawl 8 once again cooperates with stop 7 to hold the vane 4 in its unoperated position. The cap 18 and screw 17 are then replaced. Any accumulated liquid in the wave guide then collects in the lower portion 19 of housing H and can be drawn off by removing drain block 20 provided in the bottom of the lower portion 19. The lower portion 19 is thus seen to act as a sump for the collection of any liquid which accumulates within the wave guide. The wave guide is now refilled with gas and when the normal working pressure within the guide is restored valve 11a opens and remains open until gas pressure within the bellows 9 is equal to that within the guide.

Although operation of the vane 4 to close the bore of the wave guide has been described with reference to pressure within the wave guide, dropping due to fracture of the wave guide, it is to be understood that should gas pressure within the guide fall for any other reason then, if the pressure drop is suflicient to cause pawl 8 to disengage from stop 7, vane 4 will be rotated to an operative position in a manner similar to that already described.

In a wave guide having an internal diameter of 2 inches and used for transmission of signals in the frequency band 35-400 Gc./s. the slot 3 typically has a width of A".

Two annular flexible tubes such as 16 may be provided, one on either side of the vane 4. Alternatively, the vane may have a tube 16 on one side and the opposite side of the vane may be coated with a resilient material, the vane having sufiicient axial freedom of movement to permit the coated side to be forced into sealing engagement with the adjacent wave guide end whilst the tube 16 engages with the other wave guide end as previously described.

Although, as described the vane 4 may be provided with means for sealing the bore of the wave guide this is not an essential feature of the invention and the seal may be dispensed with, the wane 4 nevertheless preventing flow of unwanted material such as water or other liquid, from one section of wave guide to the next. When no sealing means are used it is advantageous that the lower portion 19 of the housing H be enlarged so that the level of water or other liquid accumulating under fault conditions would remain below the level of the wave guide tubes so that such liquid would not pass from the faulty length of the tube around the vane and into the adjacent section of the wave guide.

I claim:

1. A pressure responsive wave guide valve comprising a wave guide section, a gap in the wave guide section wall extending transversely of the longitudinal axis of the wave guide section, a gas-tight housing surrounding the gap on the exterior of the wave guide section, an axle within the housing extending parallel to the longitudinal axis of the wave guide section, a closure device rotatable about the axle, the closure device having an inoperative position in which it is located within the housing and being capable of rotation through the said gap into an operative position in which it closes the wave guide section bore, resilient means for rotating the closure device, movable means biasing the closure device in the said inoperative position, and an actuating mechanism including a device responsive to pressure within the wave guide section for moving the biasing means to permit rotation of the closure device by the resilient means to the said operative position when the pressure within the wave guide section falls below a predetermined magnitude.

2. A pressure responsive wave guide valve according to claim 1, in which the closure device has means for sealing the wave guide section bore on at least one side of the closure device when the closure device is in the said operated position.

3. A pressure responsive wave guide valve according to claim 1, in which the housing forms on the underside of the wave guide section a sump suitable for the collection of liquid.

4. A pressure responsive wave guide valve including a circular wave guide section, a gap in the wave guide section wall extending transversely of the longitudinal axis of the wave guide section, a gas-tight housing surrounding the gap on the exterior of the wave guide section, an axle extending parallel to the longitudinal axis of the wave guide section, a closure vane mounted for rotation about the axle, the vane having an inoperative position in which it is located within the housing and being rotatable for insertion through the gap into an operative position in which it closes the bore of the wave guide section, resilient means urging the vane towards the said operative position, a retaining member movable between first and second positions, in the first position the retaining member holding the vane in the said inoperative position against the resilient means, and in the second position the retaining member permitting rotation of the vane by the resilient means to the said operative position, and an actuating mechanism including a device responsive to pressure within the wave guide section and arranged to move the retaining member from the said first position to the said second position when the pressure within the wave guide section falls below a predetermined magnitude.

5. A pressure responsive wave guide valve according to claim 4, in which the pressure responsive device is a resilient bellows, and including within the housing a oneway valve having an inlet side exposed to pressure within the wave guide section bore and having an outlet side, means connecting the outlet side of the one-way valve and the interior of the said bellows, and the one-way valve arranged to open when pressure within the wave guide section exceeds pressure within the said bellows.

6. A pressure responsive wave guide valve according according to claim 5, in which on at least one side the said vane has a hollow flexible member arranged for cooperation with the wall of the wave guide section when the vane is in the said operated position, and a tubular member connected to the hollow flexible member, the tubular member being adapted to register with the inlet side of and to open the said one-way valve when the vane is in the said operated position, whereby the hollow flexible member is inflated by the said bellows and forms a gas-tight seal with the said wall of the wave guide section.

7. A pressure responsive wave guide valve according to claim 5, in which the housing forms on the underside of the wave guide section a sump suitable for the collection of liquid.

8. A pressure responsive wave guide valve including a wave guide section, a gap in the wave guide section wall extending transversely of the longitudinal axis of the wave guide section, a gas-tight housing surrounding the gap on the exterior of the wave guide section, an axle within the housing extending parallel to the longitudinal axis of the wave guide section, a closure vane mounted for rotation about the axle, the vane having an inopcrative position in which it is located within the housing and being rotatable for insertion through the gap into an operative position in which it closes the bore of the wave guide section, resilient means for rotating the vane, a pawl movable between first and second positions, in the first position the pawl holding the vane in the said inoperative position against the action of the resilient means, and in the second position the pawl permitting the resilient means to rotate the vane into the said operative position, a resilient bellows located within the housing, a one-way valve having an inlet side exposed to pressure within the wave guide section and having an outlet side, means connecting the outlet side of the one-way valve and the interior of the flexible bellows, the one-way valve being arranged to open when the pressure on its inlet side is greater than the pressure on its outlet side, a member projecting from one end of the flexible bellows and movable by the bellows to shift the said pawl from the first position to the second position upon the pressure within the wave guide section falling below a predetermined magnitude, a hollow flexible member on at least one side of the vane for co-operation with the wall of the wave guide section, a tubular member connected to the hollow flexible member and adapted to register with the inlet side of and to open the said one-way valve when the vane is 25 in the said operative position, whereby the bellows inflates the hollow flexible member to form a gas-tight seal with the wall of the wave guide section.

9. A pressure responsive wave guide valve according to claim 8, in which the one-way valve comprises a cylinder and a piston movable within the cylinder, the piston having a stem extending through one end of the cylinder, a drilling in the piston stern arranged to communicate with the interior of the cylinder only when the one-way valve is open, and in which the tubular member connected to the said hollow flexible member is adapted to register with the piston stem and move the piston to open the oneway valve when the vane is in the said operative position.

10. A pressure responsive wave guide valve according to claim 8, in which the housing forms on the underside of the wave guide a sump suitable for the collection of liquid.

11. A pressure responsive wave guide valve according to claim 8, in which the wave guide section is a circular wave guide.

References Cited in the file of this patent UNITED STATES PATENTS 2,566,774 Otis Sept. 4, 1951 

1. A PRESSURE RESPONSIVE WAVE GUIDE VALVE COMPRISING A WAVE GUIDE SECTION, A GAP IN THE WAVE GUIDE SECTION WALL EXTENDING TRANSVERSELY OF THE LONGITUDINAL AXIS OF THE WAVE GUIDE SECTION A GAS-TIGHT HOUSING SURROUNDING THE GAP ON THE EXTERIOR OF THE WAVE GUIDE SECTION, AN AXLE WITHIN THE HOUSING EXTENDING PARALLEL TO THE LONGITUDINAL AXIS OF THE WAVE GUIDE SECTION, A CLOSURE DEVICE ROTATABLE ABOUT THE AXLE, THE CLOSURE DEVICE HAVING AN INOPERATIVE POSITION IN WHICH IT IS LOCATED WITHIN THE HOUSING AND BEING CAPABLE OF ROTATION THROUGH THE SAID GAP INTO AN OPERATIVE POSITION IN WHICH IT CLOSES THE WAVE GUIDE SECTION BORE, RESILIENT MEANS FOR ROTATING THE CLOSURE DEVICE, MOVABLE MEANS BIASING THE CLOSURE DEVICE IN THE SAID INOPERATIVE POSITION, AND AN ACTUATING MECHANISM INCLUDING A DEVICE RESPONSIVE TO PRESSURE WITHIN THE WAGE GUIDE SECTION FOR MOVING THE BIASING MEANS TO PERMIT ROTATION OF THE CLOSURE DEVICE BY THE RESILIENT MEANS TO THE SAID 